超(超)临界锅炉吹管调试过程给水控制方法研究

Study on Feedwater Control Method in Blow-pipe Commissioning for Ultra-supercritical Boiler

针对超(超)临界直流锅炉在降压吹管中传统的锅炉给水控制方法易造成机组主燃料跳闸的事故,提出以启动循环泵(boiler water circulating pump,BCP)出口流量作为控制点的给水控制方法。分析降压吹管过程中水冷壁与储水箱内工质的热力学变化及流量测量原理,认为BCP出口流量能反映锅炉水冷壁及储水箱内的水量。通过理论计算得到降压吹管过程中的最小给水流量,总结出控制炉水循环泵出口流量不低于正常流量的60%,可以实现给水的优良控制。最后,将该给水控制方法成功应用于某电厂的吹管和主燃料跳闸过程,表明该方法具备实际工程应用性。

Aiming at accident of main fuel trip caused by traditional boiler feedwater control method in progress of decom- pression blow-pipe for ultra-supercritical direct current boiler, this paper proposes one feedwater control method which is to start outlet flow of boiler circulating pump for conducting as the control point. By analyzing thermodynamic changes and flow measuring principles of working medium in the water wall and storage water tank during the period of decompression blow-pipe, it considers that the outlet flow is able to reflect water quantity. By theoretical calculation on minimum feedwater flow, it draws a conclusion that it is able to realize good control on feedwater by controlling the outlet flow of boiler water circulating pump not lower than 60% normal flow. On the basis of application of this feedwater control method in blow-pipe and main fuel trip in some power plant, it shows that this method is feasible in engineering application.